1. Field of Invention
This invention relates to an improved water guard for a seal assembly of the type employed with oil film bearings in rolling mills.
2. Description of the Prior Art
A previously developed sealing arrangement for a rolling mill oil film bearing is shown in FIG. 1. In that arrangement, the roll 10 has an end face 12 joined by an intermediate tapered section 14 to a reduced diameter section 16 surrounded by a sleeve 18. The sleeve is keyed or otherwise secured to the roll neck, and is journalled in a bushing 20 fixed within a roll chock 22. Oil is supplied continuously at the bearing interface between the sleeve and bushing, and the seal assembly generally indicated at 24 surrounds the intermediate tapered neck section 14 to prevent oil from escaping from the bearing and also to prevent contaminants such as cooling water, mill scale, etc. from penetrating into the bearing.
The seal assembly includes a circular flexible flanged neck seal 26 and a flinger ring 28, both being carried on the roll for rotation therewith, and a seal end plate 30 and a coolant seal 32, all being fixed in relation to the bearing chock 22.
The coolant seal 32 has a radial mounting flange 34 integrally joined at its inner periphery as at 36 to a sealing flange 38 extending angularly therefrom into sealing contact with the roll end face 12. The mounting flange has holes 40 through which protrude screws 42 which are threaded into the seal end plate 30. The seal end plate has an integral circular shoulder 44 which protrudes axially towards the roll end face 12, and which acts as a bumper against which the roll end face may bear during an extreme axial "floating" of the roll in relation to the chock. While this arrangement has the capability of operating in a generally satisfactory manner, it does embody several drawbacks. For example, the shoulder 44 can be damaged by contact with the rotating roll end face 12, and this can eventually lead to a need to replace the seal end plate 30 at a considerable cost to the mill owner. Also, because the shoulder 44 protrudes axially beyond the end of the seal end plate flange 46, the overall axial length of the seal end plate coating is unnecessarily increased, resulting in a concomitant increase in its weight and cost.
As best can be seen by additionally referring to FIG. 2A, a further drawback stems from the fact that the diameters d.sub.1 of the holes 40 in the mounting flange 34 preferably should be considerably larger than the diameters d.sub.2 of the screws 42, so as to allow for some relative shifting or "play" between the mounting flange and the screws. Thus, when a given sized coolant seal is mounted on a seal end plate having a given radius R.sub.1, the screws 42 may be centrally located in their respective holes 40. However, as shown in FIG. 2B, in the event that the same sized coolant seal is used in a smaller bearing assembly where the seal end plate has a smaller radius R.sub.2, then a relative shifting and distortion of the mounting flange 34 and its respective holes 40 will occur relative to the screws 42 as a result of the coolant seal being bent into a smaller circle. Because of this shifting and distortion, the screws 42 cannot be relied upon to accurately control the spacing 48 between the inner periphery of the coolant seal and the cylindrical surface 50 of the flinger ring 28. If this spacing is not adequate, the coolant seal and/or the flinger ring will wear prematurely.